Baffle plate for mufflers



Nov. 7, 1939. B. G. ROBBINS BAFFLE PLATE FOR MUFFLERS Filed Feb. 21, 1958 Patented Nov. 7, 1939 UNITED STATES ZJJQ OM RAFFLE PLATE FOR MUFFLERS Brewster G. Robbins, Utica, N. Y., assignor to Herbert S. Powell, Utica, N. Y.

Application February 21, 1938, Serial No. 191,776

2 Claims.

The present invention relates to new and useful. improvements in mufflers for quieting the exhaust of internal combustion engines, and more particularly to improved baifie plates for mufflers,

i and to an improved method of making such balile plates.

An object of the invention is to eifect a substantial saving of material in making baffle plates for mufilers, and to this end, the invention contemplates the forming of baffle plates from square or substantially square metal blanks.

A further object of the invention is to provide a baffle plate made according to the above method, which will afford a smooth tight fit entirely around the interior surface of the muffler casing, and which will also provide relatively large spaced welding areas around the interior surface of the muffler casing so as to facilitate securing of the baffle plate thereto.

:0 The above and other objects of the invention will in part be obvious, and will be hereinafter more fully pointed out.

In the accompanying drawing:

Figure l is a side elevation showing the assembled muffler tubes and baffle plates with a portion of the casing shown in section.

Figure 2 is a fragmentary plan View showing a metal sheet from which the baffle plate blanks are cut.

:0 Figure 3 is a plan view of a substantially square blank from which a baffle plate is formed.

Figure 4 is an end view showing a baffle plate made from the blank of Figure 3.

Figure 5 is a rear view of Figure l. 35 Figure 6 is a sectional view taken along the line 6-5 of Figure 4.

Figure '7 is a plan view of a square blank from which a baffle plate may be formed.

Figure 8 is a sectional view through one of the i0 baffle plates made from the blank of Figure '7.

The invention is particularly concerned with the provision of baffle plates for a muffler which is provided with a plurality of expansion chambers. The baffle plates define these expansion 45 chambers. and it is desirable to provide a tight between each baffle plate and the interior surface of the muffler casing so that each expan sion chamber will be substantially tight. Ordinarily these baffle plates are drawn from a cir- 0 cular blank, and the flange which is formed must l be of sufficient width to provide welding areas for l securing the baffle plates to the muffler casing. In

drawing a circular blank to form a circular baffle plate, the flange of each bairle plate is often wrinkled. or buckled due to the crowding of the metal during the forming operation. Thus, it is difficult to provide a tight connection between such baffle plates and the muffler casing. In order to overcome this difficulty, it been necessary to use pads to prevent this wrinkling or buckling 5 of the flange. It is, of course, desirable to pro vide relatively large welding areas on the balile plates in order to facilitate the securing thereof to the muffler casing. For this reason, it is necessary to provide a relatively wide continuous 10 when drawing such baffle plates from circular blanks.

The present invention is concerned with overcoming the above mentioned difficulty, and con-- templates the forming of baffle plates from square or substantially square metal blanks. In tins manner, there can be provided a relatively narrow smooth flange portion which will provide a substantially tight fit with the interior surface of the muffler casing. Such a plate can be formed by simply using a plunger and a round die without a pad. Because of the fact that the baffle plate is drawn from a square blank, there will be provided relatively large spaced extensions which provide relatively large welding areas for securing the baffle plate to the muffler casing.

Referring more in detail to the accompanying drawing,- and particularly to Figure 3., there is shown a muffler assembly with a portion of the muffler casing in section. This assembly include a muffler casing C and a plurality of tubes i i. There are preferably provided three of these tubes, and the tube it extends through an end plate 52 which provides an inlet for the muffler. This tube Ill terminates short of the opposite end plate it. The tube if extends through the end plate l3 and terminates short of the end plate thus providing an outlet for the er. The third tube terminates short of both end plates and provides a passage for the from the tube l 0 to the tube 5 f. Mount-ed within the C are a plurality of spaced baifle plates M, through which the tubes extend. The baffle plates are secured to the interior surface of the muffler casing, and are provided with perforations between adjacent baffle plates so as to permit expansion and contraction of the gases of combustion passing through the muffler.

Each of the bafile plates ll, according to the present invention, is made from a square or sub- 0 stantially square metal blank so that substantial saving of sheet metal results in the cutting of these blanks. As shown in Figure the baffle plates l4 may be formed from a square metal blank S or from a substantially sqare metal blank, that is, one wherein the tips T have been cut off. The square metal blank S is shown in Figure 7, and the substantially square metal blank ST is shown in Figure 3.

In the manufacture of a baffle plate from the substantially square blank ST, shown in Figure 3, a circular die and plunger are employed. The die and plunger are of such diameter that the blank is formed with relatively narrow flange portions I6 which merge into spaced enlarged portions H. In forming such a blank, there will result a smooth and even flange including the narrow portions I6 immediately adjacent the peripheral edge of the body portion of the formed baflle plate. Any tendency for the metal to crowd or buckle in the region of the narrow portions I6 will be counteracted by the tendency of the metal to flow from these portions into the enlarged portions IT. A baffle plate made according to this method assures a smooth and even surface for providing a tight fit with the interior surface of the mufiler casing. The enlarged portions Il are, as illustrated, elongated axially of the muffler casing and provide enlarged areas to facilitate the welding of the baflle plate to the mulller casmg.

The body portion of the baffle plate I4 extending across the muffler casing is punched or otherwise cut to provide openings I5 through which the muffler tubes extend.

As shown in Figures 7 and 8, the baffle plate Ida is made from a square blank S. The enlarged portions Ila remain pointed in this form of baffle plate since the tips T of the metal plank are not removed. This baffle plate is also provided with openings [5a through which the mufller tubes extend.

According to the present invention, there is thus provided a bafile plate which is formed from a square or substantially square metal blank. The baille plate is one which includes at least a narrow portion entirely around the periphery thereof Which is smooth so that it will provide a tight fit with the interior of the muffler casing. The relatively narrow flange portions I6, Ilia merge into spaced enlarged portions II, Ila. Thus, there is no buckling or crowding of the metal around the periphery thereof in the region of the reduced flange portions I6, I60. so that a tight and exact fit is provided with the interior surface of the muffler casing. The axially elongated or enlarged portions I1, Ila serve to strengthen the baffle plate and muffler and also provide enlarged areas for conveniently welding the baflle plates to the mufller casing.

The present invention thus provides a bafile plate for mufflers which is highly efhcient, which is strong and durable, and which permits a maximum saving of material during the manufacture thereof. It is to be clearly understood that various changes in the details of constrution and arrangement of parts may be made without departing from the scope of the invention as set forth in the appended claims.

I claim:

1. A baflle plate for mufilers, comprising a body portion adapted to extend across the muffler casing and a flange disposed around the peripheral edge of said body portion and extending axially of the muffler casing, said flange affording a continuous smooth tight fit entirely around the interior surface of the muffler casing and including spaced relatively narrow portions tightly fitting against the interior surface of the muffler casing for preventing bending of the baffle plate and also including spaced relatively large portions tightly fitting the interior surface of the mufller casing for providing enlarged areas for welding the baffle plate to the mufller casing.

2. A baffle plate for mufflers, comprising a body portion adapted to extend across the mufller casing and a flange disposed around the peripheral edge of said body portion and extending axially of the muffler casing and at substantially right angles to the body portion, said flange affording a continuous smooth tight fit entirely around the interior surface of the muffler casing and including spaced relatively narrow portions tightly fitting against the interior surface of the muffler casing for preventing bending of the baffle plate and also including spaced relatively large substantially triangular portions tapering away from the narrow portions and said body portion and tightly fitting the interior surface of the muffler casing for providing enlarged areas for welding the baffle plate to the muffler casing.

BREWSTER G. ROBBINS. 

